Four-cycle internal-combustion engine



Aug. 20, 1929.

G. A. PRINDLE FOUR-CYCLE INTERNAL COMBUSTION ENGINE Filed Oct. 15, 1924 3 Sheets-Sheet Aug. 20, 1929. G. A. PRINDLE FOUR-CYCLE INTERNAL COMBUSTION ENGINE Filed Oct. 15. 1924 5 Sheets-Sheet 2 Aug. 20, 1929.

G. A. PRINDLE FOUR-CYCLE INTERNAL COMBUSTION'ENGINE 3 Sheets-Sheet 3 Filed Oct. 15. 1924 Patented Aug. 20, 1929.

GLEN .A.v PRINDLE, F NEAR REASNOR, IOWA.

FOUR-CYCLE INTERNAL-COMBUSTION ENGINE.

Application filed October 15, 1924. Serial No. 743,779.

This engine'is a development of the twocycle internal .combustion engine, patent to Prindle, No. 1,593,880, issued J uly 27, 1926.

The object of this invention is an internal combustion engine that is efficient and economical in the use of fuel and maintains full sea-level power at high altitudes without the use of a separate blower or supercharger.

Figure 1 is a vertical transverse sectional view parts being broken away and in sections.

Figure 2 is a view of the under side of the cylinder head on the line 22 Figure 1, showing the inlet valve head, the exhaust valve head and the spark-plug holes.

Figure 3 is a cross-sectional view on the line 33 Fig. 1 showing air ports thru the cylinder wall andair ports thru the sleeve valve, said air ports being placed at an angle with respect to the radii of the cylinder.

Figure 4 is a cross-sectional view on the line 44 Fig. 1 showing rich gas ports thru the cylinder, rich gas ports thru the sleeve valve and passages thru the piston, said ports and passages being placed at an angle with- .respect to the radii of the cylinder.

Figure. 5 is a verticaL transverse sectional View of another embodiment of my invention, parts being broken away and in section.

Figure 6 is a cross-sectional view on the line 66 Fig. 5 showing ports thru the cylinder and ports thru the sleeve valve, said ports being placed at an angle with respect to the radii of the cylinder.

Figure 7 is a vertical transverse sectional view of still another embodiment of myinvention, parts being broken away and in sec tions.

Figure 8 is a vertical transverse, view of the sleeve valve actuating cam that may be used in some of the embodimentsof my invention.

Figure 9 is a fragmentaryview showing the valve actuating mechanism, and the crank-casedivided into tight compartments.

Figure ,10 shows the pressure control means.

Figure 11 shows the sleeve valve actuating spring and the tight partition in the crankcase.

, Referringto the drawings thecrank-shaft exhaust valve actuating cam 66 Figure 9 I and sleeve valve actuating cam 23; and the valve 25, inlet chamber 26, outlet valve 27 and outlet chamber'28 are of special design.

The operation of the engine is as follows:

Each time the piston 14 moves upward toward the cylinder head 13 air enters the crank case 24 thru air inlet 38, air pipe 37, inlet chamber 26 and non-return valve 25. On each down stroke of the piston toward the crank case air is forced thru the nonreturnvalve 27 into the outlet chamber 28.

On the suction stroke of the piston air is drawn thru air inlet 38, air pipe 37, inlet passage, 4 and around inlet valve 3, said "inlet valve 3 being held open at this time by means of a cam Figure 9 which engages the lower end of pushrod 7 raising same which in turn opens the inlet valve 3 thru the agency of rocker-arm 8. This cam 65 is attached to cam-shaft 39, said cam-shaft being driven at one-half crank-shaft speed by suitable means such as gearing or chain (not shown). As the piston nears the end of its downward stroke thecam 23 (which is attached to cam-shaft 39) attains such a position that the sleeve valve 20 is allowed to movedownward. actuated by the friction ofthe piston 14 moving downward within the said sleeve valve-20 and, if necessary,,..by the additional downward pressure of a spring, 67 Figure 9. By the time ports 34 in the sleeve valve 20 register with passages .29 in the piston the sleeve valve 20 is moving with the same speed and in unison with the piston 14. Just before passages 29 and ports 34 begin to register with air ports 17 the inlet valve 3 is allowed to close. When passages 29 and ports 34 register with air ports 17 air under pressure from outlet chamber 28 passes thru-air pipe 40, air passage 16, air ports-17, ports 34 and passages 29 into cavity 30 and thence into the interior of the cylinder driving the products of the previous combustion from passages 29 and cavity 30.

. On account of the shape of the ports 17 and crank-case 24 with its associated parts, inlet 34 and the passages 29 this air is given a rapid whirling motion. Farther downward movement of the piston and sleeve valve causes ports 33 in the sleeve valve to register with air ports 17 in the cylinder wall allowing air under pressure to pass from 28 thru 40, 16, 17 and over the top of the piston 14 into the interior of the cylinder. On account of the shape of 17 and 33 this air is also given a rapid whirling motion. At this time passages 29 and ports 34 register with rich gas ports 19 andair from outlet chamber 28 passes thru air pipe '40 into carburetor 41 where it takes up fuel tov form a rich mixture then it enters'rich gas passage 18 and passes thru 19, 34 and 29 into cavity 30 and thence into the interior of the cylinder. On account of'the shape of the ports 19 and 34 and the passages 29 this gas is given a rapid whirling motion. Figures 1, 3 and 4 show the engine with the various parts in this position, that is with the piston 14 and the sleeve valve 20 in their lowest position on the intake stroke. As the piston and sleeve valve move upward the passages 29 and ports 34 again register with air ports 17 but at this time the pressure inside the cylinder is nearly. great as the pressure in 16 so that but a small amount of air passes thru the ports and passages. The sleeve valve 20 soon reaches its limit of travel as determined by the cam 23 and the cylinder head 13, the piston moves on upward on the compression stroke and at the proper instant ignition takes place in the whirling rich gas in the central part of the combustion chamber. After the piston reaches top dead center it passes downward on the power stroke, as the piston nears the end of the power stroke the exhaust valve is opened, as in an ordinary four-cycle engine, this exhaust valve is opened by means of a cam 66 as was the case of the inlet valve It should be noted thatthe cam 23 still holds sleeve valve 20 in its highest position with ports 17, 19, 33 and 34 closed so no air, rich gas or exhaust gas can pass thru them. After passing lower dead center on the power stroke the piston passes upward on the exhaust stroke driving before it the products of the previous combustion. After the piston reaches top dead center it starts downward on the suction stroke. The exhaust valve may be timed to close at top dead center or it may be timed to stay open for a while after the piston has started downward on the suction stroke and the inlet valve has opened as this will tend to more thoroughly clear the exhaust gases from the combustion chamber. This completes the cycle.

It will be noted that air isdrawn into the cylinder during the greater part-of the suction stroke and that air is admitted to the crank-case during the compression stroke and during the exhaust stroke to be forced into the outlet chamber during the power stroke and the suction stroke respectively. This air passes, part of it directly and part of it v given a rapid whirling motion upon entering the cylinder. This rich gas and the air are still whirling'rapidly at the time of ignition which causes the flame to be quickly carried to all parts'ot the combustible charge.

On account; of the centrally located cavity 30 in the top of the piston and the flange surmounting the piston and surrounding the cavity, the whirling rich gas is kept near the center of the'cylinder with a surrounding shell of air, free or nearly free from gas. Ignition takes place in the rich easily burning mixture and the flame burns out into an excess of air or supporting atmosphere allowing all the hydrogen and all the carbon in the fuel to combine with the oxygen in the air, the surrounding shell of air preventing the loss of a large amount ofh'eat thru the piston and the cylinder wall during the power stroke.

\Vith the rich gas stratifiedcentrally of the combustion chamber at the time of ignition it is possible, over most of the power and speed range of the engine, to control the power output and speed by the use of the rich gas throttle 46 alone, while enough air is admitted to keep the compression as high as desired. From the above it will be seen that this engine is efiicient and economical in the use of fuel and maintains full sea-level power at great altitudes without the use of a separate blower or supercharger. An exhaust driven or other type of supercharger may be used with this engine if it is desired to have this engine maintain full sea-level power at such great altitudes that the air weighs less than one-third of what it weighs at seacam 23 Fig. 1, the sleeve valve 20 will move down slightly at the end of the power stroke causing ports .34 to register with ports 17 (after the exhaust valves have opened) allowing a small amount of air to pass into the cylinder to help clear the spent gas from the larger.

{cylinder and combustion chamber by formthru the piston are the same as those in Fig.

4 except that they may be higher and hence There is but one series of ports 19 in the cylinder wall, and but one series of ports 34: in the .sleeve valve wall. These ports are the same as'19 and 34 Fig. 4: except that they may be higher and hence larger. Air alone is drawn into the cylinder during the greater part of the suction stroke and all the'air from 28 passes thru carburetor 56 .where it takes up fuel to make a mixture that is richer than normal, then passesthru 57, 19, 345, 29 and 30 into the cylinder during the last of the suction stroke and the first of the compression stroke, the rest of the cycle is the same as-described on pages 2, 3 and 4. If desired the carburetor may compression stroke.

be connected to 58, the inlet to the inlet chamber 26 and crank-case 24,, in place of between 28 and 57' as shown in Fig. 7, in this case a pipe will have to be connected between 28'and 57 as shown at 59 Fig. 5.

Figure 5 is still another-embodiment of my invention. In this case an ordinary piston 53 is used, ports 51 in the cylinder wall are the same as ports 19 Fig. 7 and ports 52 are-the same as 34 Fig. 7. The carburetor 60 is connected to inlet pipe 61, which in turn is connected to inlet chamber 26 and inlet passage 4. This allows a fuel mixture of the correct proportions of fuel and air, to be drawninto thecylinder during the greater part of the suction stroke, and into the crank-case during the compression stroke, and during the. exhaust stroke. This fuel mixture is forced into the outlet chamber 28 during the power stroke and during the suction stroke respectively and passes from 28 thru 59, 57, 51 and 52 into the interior of the cylinder during the last of the suction stroke and the first part of the The rest of the cycle is the same as an ordinary four-cycle engine. -If it is desired to keep fuel mixture from the interior of the crank-case, carburetors'may be placed as shown in Fig. 11.

In'a multicylinder engine, outlet chamber '28 need be no more than a passage way for thecontents of the crank-case; the smaller the number of cylinders the larger the outlet chamber must be. The crank-case must be divided into compartments by partitions 68 Figures 9 and 11 to co-act with the pistons to form compressors, of if desired a separate compressor may even be used in place of using the crank-case.

.I claim! 7 1. In a four-cycle internalcombustion engine, a cylinder having the combination of air inlet, ports intermediate the ends thereof and rich gas inlet ports below said air in let ports, means to open and to close said ports at predetermined points in the cycle ofoperation, air inlet ports. and exhaust ports at the upper end and means to open and to close said ports at predetermined points in the cycle of operation.

2. In aninternal combustion engi controlled air inlet ports and valve controlled rich gas inlet ports intermediate the ends no, a cylinder having the combination of, valve thereof, valve controlled inlet port at the upper end and valve controlled exhaust port at the upper end. i

3. In aninternal combustion engine, a

cylinder having the combination of, valve controlled air inlet ports intermediate the ends thereof, valve controlled rich gas inlet ports below said air inlet ports,-valve controlled inlet port at the upper end and valve controlled exhaust port at the upper end.

4. In an internal combustion engine, a

cylinder having the combination of, valvecontrolled air inlet port at the upper end,

valve controlled exhaust port at the upperi end and valve controlled air inlet ports intermediate the ends thereof and rich gas in-.;.

let ports below the air ports, said air inlet ports and rich gas inlet ports being placed at an angle with respect to the radii of the cylinder.

5. In a four-cycle internal combustion engine, a sleeve valve suitably slidably mounted Within the cylinder, said sleeve valve having intermediate the ends thereof air inlet ports and rich gas inlet ports, a piston suitably slidably mounted within the sleeve valve, said piston having a cavity located centrally of the top thereof, a flange surrounding the cavity and surmounting the piston and passages near the top of the piston leading from the periphery thereof to the central cavity, i

said passages being adapted to register with the inlet ports in the sleeve valve when the inlet ports in the sleeve valve register with the inlet ports in the cylinder wall.

6. In a four-cycle-"internal combustion engine, a sleeve valve suitably slidably mounted within the cylinder, said sleeve valve having air inlet ports intermediate the ends thereof and having'rich gas inlet ports below the air inlet ports, a piston suitably slidably mounted within a sleeve valve, said piston being furnished with passages near the top leading, at an angle with the radii ofthe piston, from the'peripheryof the piston to a cavity located centrally of the-top thereof,

said cavity being surrounded by a flange which surmounts the piston, the passages in -the piston being adapted to register with 7. An internal combu stion engine having in combination a cylinder having ports intermediate the ends thereof, ports at theupper end and means to open and to close said ports, a sleeve valve mounted within the (-vlinder, ports intermediate the ends thereof, said portS being adapted to register with the ports in the cylinder-wall at predetermined intervals in the cycle of operationand means to operate said sleeve valve, :1 piston operating within the sleeve 'alve, said piston having a cavity located centrally of the top thereof, a flange surrounding the cavity and ran-mounting the pistol] and passages thru the piston near the top leading 'from the periphery to the central cavity, said passages being adapted to register with the ports in the sleeve valveat certain intervals in the cycle of operation, a cam for actuating the sleeve valve and me us to operate the cam, a crank-case provide tl with a non-return inlet valve and a non-return outlet valve, an outlet chamber connected to the outlet of the crank-case outlet non-return valve. and connected to the inlet ports in the cylinder \vall intermediate theends thereof, and means to keep the pressure in the outlet chamber within the desired limits.

In testimony whereof I aflix my signature. v

GLEN A. PRINDLE. 

